The present invention relates, in general, to the field of sound producing prosthetic devices for use by laryngectomized patients, and in particular, relates to a self-contained intra-oral artificial larynx and an improved battery pack therefor.
Many devices have been suggested for providing speech capability to laryngectomized patients. The most successful and important of these devices known to the present applicants is the artificial larynx described in detail in the immediate parent application to the present application, i.e., application Ser. No. 438,376, filed Nov. 1, 1982. In that application, various prior art techniques of artificially producing speech by a laryngectomized patient are discussed. Unlike the prior art devices which had relied upon extra-oral components, the device disclosed and claimed in the parent application is one which resides entirely within the mouth of the patient and which is incapable of visual detection.
The device disclosed and claimed in the parent application includes, inter alia, a power source, a signal generator, a speaker and tongue activated switches, all of which are mounted to a dental prosthesis and situated within the wearer's mouth. All of the aforementioned components, as well as others, are formed in the body of a dental prosthesis which is formed of conventional dental prosthetic materials, such as an acrylic polymer, which is shaped to fit comfortably against the roof of the wearer's mouth.
Because all of the components of the device of the parent application are situated on an intra-oral dental appliance, a maximum size constraint greatly affects the power source which may be employed. The power source must be extremely thin because the dental appliance fits against the roof of the mouth. If the appliance is unduly thick it provides an obstacle to swallowing. Because the power supply is subjected to a severe maximum size constraint, the device of the parent application employs a unique combination of tongue controls for permitting convenient intermittent use, novel power saving circuitry and tuned acoustic amplification to permit the artificial larynx to be used for longer periods of time before the power source is exhausted. In the embodiment shown in FIG. 1 of the parent application, the batteries are entirely sealed within the dental prosthesis such that the use of replacement of the batteries is impossible. Alternate embodiments are suggested wherein batteries may be replaced.
The provision of an intra-oral artificial larynx having replacement batteries is not without difficulty. In order to provide an intra-oral artificial larynx with replaceable batteries, it is necessary to provide a dental appliance having an opening therein to a battery compartment. Such an opening to the battery compartment creates certain problems. First, the opening provides a route for the invasion of saliva into the battery or power source compartment of the artificial larynx. Saliva, however, is conductive, and may cause the batteries to short circuit which, in turn, causes the artificial larynx to be rendered inoperative. Secondly, the saliva, being conductive, may cause corrosion between the anode and cathode of the batteries. The corrosion may be harmful, not only to the artificial larynx itself, but also to the patient as well. Thirdly, if the battery compartment is not adequately sealed, the batteries may become dislodged and swallowed which may be harmful to the patient.
Another difficulty encountered in providing replaceable batteries for an intra-oral artificial larynx resides in the fact that the batteries are, and of necessity must be, relatively small thus causing them to be difficult to manipulate with the fingers. This is especially true for older and perhaps handicapped patients. It may be difficult for such patients to manipulate the small batteries required for the intra-oral artificial larynx. It may also be particularly difficult to ensure that the batteries when inserted are properly inserted with the correct polarity.
It would be desirable to provide an intra-oral artificial larynx which does not suffer from the aforementioned disadvantages. It would be further desirable to provide an intra-oral artificial larynx having a removable battery pack.
It is still further desirable to provide an intra-oral artificial larynx with a removable battery pack which, when in place, is completely sealed from saliva found in the intra-oral cavity.
It would still be further desirable to provide such an artificial intra-oral larynx having a battery pack which is easily inserted and removed.
It would be still further desirable to provide such a battery pack in a form such that the insertion of batteries having incorrect polarity is minimized or avoided.